systemd-suspend.service man page:
Note that scripts or binaries dropped in /lib/systemd/system-sleep/ are intended for local use only and should be considered hacks. If applications want to be notified of system suspend/hibernation and resume, there are much nicer interfaces available.
So what are some of these "nicer interfaces" that I can use to get notified before suspension? (would be nice if it is before n sec/min)